针对车辆的稳定性问题，基于相平面理论，通过建立二自由度车辆的扩展模型以及运用简化的魔术公式对实际的轮胎侧向力进行拟合，获得了相平面图并划分稳定的区域；研究路面附着系数和车速对相平面边界的影响，确定质心侧偏角与质心侧偏角速度β-̇β相平面及质心侧偏角与横摆角速度β-r相平面的边界函数，提出一种车辆稳定性控制方法。在建立的 Simulink与Carsim联合仿真平台上，对所设计的控制器进行验证，当系统相轨迹超出稳定区域时，以稳定边界为控制目标，控制器集成2种相平面图计算所需要的横摆力矩，将不稳定的状态拉到稳定区域，从而实现了车辆稳定性的控制。最后，与受2种单一相平面控制、横摆角速度控制和未控制的车辆进行对比，结果表明：所设计的集成控制器有一定的优势，能够显著提高极限工况下车辆的稳定性。%Aiming at the stability problems of vehicles,by establishing an extended two degrees of freedom vehicle model and using simplified Magic Formula to fit the practical tire lateral force,the stable zone boundaries of phase-plane were acquired based on phase plane theory.After studying the effects of the road frictional coefficient and vehicle speed on the phase plane of boundary,the boundary functions of the sideslip angle-sideslip angle rate calledβ-̇βphase plane and the sideslip angle-yaw rate calledβ-r phase plane were determined and the vehicle stability control method was put forward.The control strategy was validated on the co-simulation platform based on Simulink and Carsim,when the system phase traj ectory got out of the stability region,the stability control-ler would calculate the required yaw moment by combiningβ-̇βphase plane withβ-r phase plane, to limit the system within the stability boundary,and thus pulled the unstable states to the stable zone.Finally,by comparing with the two phase plane controllers,yaw rate method and the uncon-trolled case,the results showed that the integrated control method had a certain advantage and could improve vehicle stability under extreme condition obviously.
展开▼
